Radiogoniometer



H. ANTRANIKIAN RADIOGONIOMETER July 25, 1933.

3 SheetsSheet l Filed Aug. 14, 1928 H. ANTRANIKIAN RAD-IOGONIOMETER July 25, 1933.

Filed Aug. 14, 1928 3 Sheets-Sheet 2 .QRME V ikSmvi Jewel ZZZ] 1 M] autw I c July '25, 1933. 'H. ANTRANIKIAN RADIOGONIOMETER Filed Aug. 14, 1928 3 Sheets-Sheet 3 INVENTOR ATTOR Patented July 25, 1933 UNITED STATES PATENT OFFICE HAIG ANTRANIKIAN, OF PARIS, FRANCE, ASSIGNOR F ONE-HALF TO FRANKLIN '1.

MILLER, OF NEWTON, MASSACHUSETTS RADIOGONIOMETER Application filed August 14, 1328, Serial, No. 299,606, and. in France-August 16, 1927...

The present invention, though having also more general fields of utility, is more stead of in the crossed bobbins.

particularly related to radiogoniometry.

A chief object of' the present invention is to provide a new and improved radiogoniometer that shall be accurate, simple in construction, and efiicient in operation.

With the above end in view, a feature of the invention resides in a preferred radiogoniometric receiving device having two crossed loop or coil aerials for receiving the signals, fixed to the plane or other apparatus with which the radiogoniometer is intended to be used. The loop aerials are connected in series-with a common tuning condenser, and means is provided for periodically reversing the connections of one of the loop aerials. A further feature resides in a preferred transformer, one of the windings of which, say the primary Winding, is constituted of crossed parts or bobbins, the' angle between which is the same as the angle between the crossed loops, the connections of one of the .bobbins being periodically reversed synchronously with the reversal of the loop aerials. The other winding of the preferred transformer,say the secondary winding,is preferably provided with two parallel bobbins, though it may be constituted of but a single bobbin. As will be explained hereinafter, the reversal may be efiected in the parallel bobbins insired, the indications of the radiogoniommeans of a servo-motor. Additional features involve insuring a proper sensitivity of the instrument at all azimuths, and correcting for errorscaused by known local wave deviations, such as are instroduced by the ship.

O'her objects and advantages will be explained hereinafter and will be particularly pointed out in the appended claims, it being understood that it is'intended, by suitable expression in the claims, to cover all the novelty that the invention may possess.

The nature and the objects of the inventions will bemore fully explained in connection with the accompanying drawings,

in which Fig. l is a diagrammatic view of apparatus and circuits constructed and arranged according to a preferred embodiment of the present invention; Fig. 2 is a diagrammatic view illustrating a preferred coupling transformer; Fig. 3 is a diagrammatic view illustrating several methods of connecting the transformer into circuit; Fig. 4 is a similar view illustrating a preferred, automatic indicating means; Figs. 5 and 6 are diagrammatic views illustrative of preferred connections for insuring proper sensitivity at all azimuths; Fig. 7 is a diagrammatic view of a preferred mechanism intended to correct for errors, and Fig. 8 is a diagrammatic view combining the showings .of Figs. 1 and 4 into a unitary system. Y

The coil aerials or loops may be of any suitable form, having Well defined planes and having about the same pick-up area in these planes. A loop with a well defined plane of orientation may, for example, consist of a winding, equivalent to a plane coil, and having a suitable fixed surface or area and a fixed position. A receiving loop of this kind-may have any desired shape, as circular or polygonal. Two or more wlndings with a well defined plane, connected in series, are also equivalent to a loop aerial of this sort.

The two receiving loop antennae ,1 and 2 are diagrammatically shown in Figs. 1 and 8, fixed on the craft at an angle to each other, preferably a rightangle, and connected in series with a common tuning condenser 3, but with a special feature without which they would be equivalent to only a single loop. This special feature is that the connections of one of the loops are periodically reversed with respect to the remainder of the circuit. This result may be brought about, for instance, by alternately reversing the sense or direction of the windings of one of the loops with respect to the other. In the illustrated embodiment of the invention, the ends 4, 5 of the windings of this loop are periodically exchanged, relatively to the ends 6, 7 of the remainder of the circuit, by means .of a rotating commutator 8 having two insulated sectors, contacting with brushes fixed to the supports 4, 5, 6 and 7. The commutator may be continuously rotated in any well known manner, asby means of a motor, as hereinafter described. Care is taken to dispose the loop windings so that their mutual induction shall not be affected by the reversal, with the result that their total self induction shall remain the same during the two reversals. The connections may be traced as follows: from aterminal 151 at one side of the condenser 3, through the loop 2, by way of a conductor 152, to the brushes 6 and 4:; from the brush 4, byway of a conductor 154:, through the loop 1, by way' of a conductorll56, to the brushes 5 and 7 and from the brush 7 ,by way of a conductor 158, back to a terminal 160 at the other side of the condenser 3. It will be noted that when the commutator 8 occupies a position at right angles to theillustrated position, it will connect the brushes 4 and 7 and the brushes 5 and 6, thus reversing the connections of the loop 1.

This wave-receiving circuit is connected, in any suit ble manner, to the input circuit of a radiorequency amplifier, shown as two vacuum tubes 170, though it will be understood that as many tubes as desired may be used. According to the illustrated embodiment of the invention, the connections to the input circuit of the amplifier 170 are effected by means of conductors 17 2 and-174, the former of which connects the terminal 151 with the filament, and the latter of which connects the terminal 160 with the grid of the first tube 170. The primary wmding of the before-mentioned special transformer is connected, either directly or indirectly, in the output circuit of the last tube 170. In the drawings, the amplif in and detecting tubes are shown as trio es but it is obvious that, without departing from the nature of this invention, they may be replaced by other types of tube.

The combination of the two loop aerials 1 and 2, connected as illustrated and described, is equivalent, when the commutator occupies one of its positions, to a single loop, aerial havlng a resultant plane coinciding with one of the planes bisecting the angle between the loops 1 and 2. When the commutator occupies its other position, and the connections of one of the loops become there-, by reversed, the corresponding loop equivalent to the combination of the-two loops 1 and 2 has a resultant plane coinciding with the other bisecting plane. The net effect of the successive reversals, therefore, is to yield rapidly in succession two resultant, 'or phantom, loops respectively occupying planes at right angles to each other and corres onding to the planes that bisect the angles etween the loops. The incoming signal waves are thus periodically received as though they were received by these two resultant loops disposed at right angles to each other. The waves thus induced in the loo aerials by the received waves are ampli ed without proportional change in intensity by the amplifying tubes, assuming that the tubes are operated on suitable portions oftheir characteristic curves, and are thus transmitted, without proportional change, to the transformer.

One of the transformer windings, primary or secondary, comprises two crossed windingparts or bobbins, which are disposed at the same angle to each other as the angle between the crossed, Wave-energy-receiving loops 1 and 2. The other transformer Winding, secondary or primary, comprises one or more windings that may be parallel geometrically,.or in thesame plane. Either of these transformer windings is fixed, and the other is rotatable abount an axis coinciding with a diameter of the winding. The windmgparts 9 and 10, as also those indicated at 11 and 12, may be connected in series,'or parallel, as desired. 7

A preferred transformer is illustrated more particularly in Fig. 2, the two winding parts or bobbins that form between them a right angle, or any other suitable angle corresponding to that between the circuit I loops, being indicated at 9 and 10. The geometrically parallel winding. parts are indicated at 11 and 12. According to the connections illustrated in Figs. 1 and 8, the crossed winding parts 9 and 10 form the primary circuit and theparallel winding parts 11 and 12 form the secondary circuit.

The connections of one of the winding parts, preferably one of the crossed windings '9 or 10, are periodically reversed, like those'of one of theflloops, by means of a commutator 32, which may be ofsimilar construction to the commutator 8 and that is shown in Fig. 8 on the same shaft with the commutator 8.

The other windings, preferably the parallel windings 11 and 12, are not reversed. I

The connections may be traced as follows: from the plate of the last amplifier tube 17 O, by way of a conductor 176, to the primary winding part 9; thence, by way of a con-,

ductor 182, to the commutator 32. .From the commutator 32, the circuit continues, by Way of a conductor 186, to the primary winding part 10; thence, by way of a conductor 194, back to the commutator 32; and from the commutator 32, by way of a conductor 196, back to' the filament of the last amplifiertube 170. The winding parts 9 and 10 are thus shown in Figs. 1 and 8 connected in series as they pass through the commutator 32. Then the commutator 32 occupies a position at right angles to that illustrated, the conductor 182 will be connected with the conductor 194, and the conductor 186 with the conductor 196. In such a condenser 13; indifi'erently this may be diposition, therefore,"the connection to the primary winding part, relative to the Winding part 9, will be reversed. This will take place simultaneously with the reversal of the connections of the loop 1.

The result, as already described more at length in connection with the loop antennae 1 and 2, is to provide the equivalent of two transformer-winding parts, successively effective and perpendicularly disposed in the planes bisecting the planes between the winding parts 9 and 10. By making the reversals of the transformer connections synchronous with those of the loop aerials, the reversed amplified currents will affect the transformer simultaneously with the reception of the emitted-waves by the loop aerials.

An. amplifier is used between the loops and the transformer for the following reason: If the transformer was directly connected in the loop circuit, the impedance of the loops may be changed by the reversals of the connections because of the change of mutual inductance between the loops and the transformer; thence the currents would not be proportional to the electromotive forces induced in the two reversed connections of the loops, and proportionality is desirable for an accurate indication of direction.

With the loop aerials and the transformer operating in the manner above set forth, with simultaneous reversal of the loops and the transformer windings, the direction, relatively to the receiving loops (and, therefore, to the craft on which they are fixed), of the emitting source or radio'sending station (to the radio signals of which the loopaerial circuit is tuned), is obviously determined by that position of the movable part of the transformer windings relatively to the fixed part of the trans former windings, for which the intensities of reception are equal for the tWo reversals.- This equality can be observed by the pilot in any desired manner, as with the aid of a measuring instrument, or an electro-magnetic relav, as shown at 17, or by a telephone, with an audible rate/of reversals, as moreparticular= ly hereinafter described.

It will be readily understood that the result is the same if one of the parallelwinding parts, 11 or 12, is reversed, because the mutual induction of one of the couples 9, 11, or 10, 12 will change by this operation exactly as if one of the crossed winding parts were reversed. The output of the transformer will thus bethe same whether one of the crossed parts or one of the parallel parts is reversed.

It will be noted that the connection, by way of the conductor 196, back to the filament of the last amplifier tube is through rectly orthrough the high voltage.

The condenser 13, which is thus disposed in series with the primary transformer circuit, prevents the commutator 32 from affecting the direct plate current of the amplifier. It prevents also the possible formation of sparks at the commutator which sparks have a very bad effect on the amplifier as is well known. The whole is shunted by a choke coil or other impedance 14, across which the plate circuit is connected, as will be understood by persons skilled in the art.

The primary bobbins, preferably the crossed bobbins 9 and 10, may be connected in the primary circuit in various ways, three such ways being illustrated in Fig. 3. The secondary winding parts are omitted from this Fig. 3, for clearness. The first example of Fig. 3 differs from that of Fig; 1 in that the crossed winding parts 9 and 10 are electrically connected in parallel. In the second example, the winding parts 9 and 10 are apparently connected independently, but.

they are really connected in parallel through their. coupling with the plate circuit. The third example illustrates an indirect series connection of the windings. It will be understood that each winding part may be replaced .by equivalent sets of other windings, in planes of orientation as defined for the aerial loops. Obviously, no change is effected in the invention if the transformer is divided into, several parts; for instance,

if the separate parts enclosed in the dotted lines 15 and 16, Fig. 2, are separated. The two parts of the movable winding thus split up should, however, by any well known means, be caused to move together as a unit.

The secondary winding parts 11 and 12 of the transformer are connected in the input circuit ofanother amplifier, which may comprise vacuum tubes 244. The connections may be traced as follows: from the filament of the first tube 244 of the second amplifier, by way of a conductor 246, to the secondary winding part 11, thence, by way of a conductor 248, to the secondary winding part 12, and finally, by wayof a conductor 252, to the grid of the said first 'amplifier tube 244. 7

Energy from the output circuit of the second amplifier 244 is utilized to actuate To this end,

plate of the detector tube 244 of the second amplifier, by way of 'a conductor 253, to avertex ,"267 of a Wheatstone bridge 266; thence, by way of a conductor 254, to a commutator 256 shown on 13118831116 shaft with, and operated insynchronism with, the com.- mutators 8 and 32. From the commutator 256, the circuit continues, by way of a con- .ductor 258, to an energizing coil 260 of the relay 17. Thereafter, thecircuit continues, by way of a conductor 261, back to the commutator 256; and from the commutator 256, by way of a conductor 262, to the opposite vertex 269 of the Wheatstone bridge 266; thence, through one of the arms of the vv lieatstone bridge 266, to a third vertex 273, and by way of a conductor 264, through a plate battery 265, and back tothe filament of the last or detector tube 244 of the said second amplifier. The fourth vertex 271 of i the Wheatstone bridge is directly connected by a conductor27 5 with the filament of the detector tube. It will be noted that the relay 17 is bridged, through the commutator 256, across the said two opposite vertices 267 and 269 of the \Vheatstone bridge by conductors 254 and 262. The connections to the relay 17 are thus reversed simultaneously with the reversal of the loop 1 and the primary winding part 10. The output circuit of the detector tube 244 of the second amplifier, as before described, is connected will prevent the indicator from leaving its zero position.

The angle corresponding to the direction of the sending station. may obviously be read 'on a graduated or calibrated scale 328 by means of aimovable pointer or other indicator 332 cooperating with the scale and carried on the axis 22 of the movable; transformer winding; or, vice versa, by means of a fixed pointer and movable graduated scale. The indicator or index 332 may be fixed to theaxis 22, as illustrated inFigs. 4 and 8, or it may be loosely connected thereto for the purpose hereinafter explained in connection with Fig. 7. f V

Assuming that the'radiogoniometer of the present invention is, used on an air craft to which the loops are fixed, all that the pilot has to do, in order to reach his destination, is so to steer his craft that the indicator of the instrument shall remain in its zero position. The craft will then make the required,

for the two reversals.

constant angle to the direction of the waves emitted from the sending station. This constant angle will be given on the scale 3280f the movable transformer winding.

To render the indications automatic, the commutators for effecting the reversals should be continuously rotated by a suitable motor, as before stated. This instrument 17, being shown in Figs. 4 and 8 as a. polarized, null-point indicating relay having two contact members 336 and 338, will bear on one or the other of the two contact members according as the intensity of reception is stronger for the one or the other of the alternations on reverse of the connections.

According to the preferred embodiment of the invention that is herein illustrated and described, the indications are rendered automatic by causing one of the contact members,

by means of a servo-motor, to turn the movable winding in a given sense or direction, and the other contact member to turn it in the other sense. If the directions of rotational-e so chosen that the intensities of reception, for the two reversals of the'loop 1 and the transformer winding 10, shall have a tendency to become equal, the movable winding of the transformer 'will stop in the position at which these intensities are equal The angle corresponding to this position corresponds to the direction of the sending station. When the winding assumes this position, the relay 17 will occupy its zero or null position, and the motor will not be further actuated.

An arrangement for effecting automatic indication in accordance with a preferred em? .bodiment of the present invention is diagrammatically illustrated in Figs. 4 and 8. The relay 17 actuates, by means of a twogrid vacuum tube 18, a second relay 19, that is much fore powerful that the relay 17, and which energizes an electric motor 20 so that its armature shall rotate in one direction or the other, according as the relay closes one contact member or the other. The motor 20 is energized from anindependent power source S. The relay l9 bridges the plate and a grid of the two-grid tube 18 in such manner that the current flowing in the windings shall be about zero when the relay 17 occupies its, zero position. The motor 20 is provided with a shaft 40 upon which is mounted a worm 126 meshing with a gear 125 that is fixed to the axial shaft or arbor 22 of the rotatable winding, shown able winding 11, 12, in one direction or the other, according to which contact member, 336 or 338 is closed by the relay 17 until the relay 17 comes to rest in its neutral position! As before stated, the movable winding may be the winding 9, 10, in which event the other winding 11, 12 would be fixed. A magnetic The motor 20 thus rotates the movbefore pointed out, the loops and thefixed clutch 21 may be actuated along with the motor though this is not necessary.

If the connections between the relay 17 and the motor remain invariable, the movable winding will. assume stable positions for reading only in the interval between two opposite quadrants. But such stability can readily be secured when passing from a stable quadrant to the following quadrant by reversing, during such passage, the direction of rotation of the motor 20 relative to the two contact members of the relay 17. This may be eifected by exchanging the connections, either between thev two contact members 336 and 338 of the relay, or betweenthe two terminals of the armature circuit or the field circuit of the motor. Thisoperation may, however, be carried out automatically by means of cams, mounted on the axis 22 of the movable winding and which may be caused to open and close the necessary contact members at the proper time.

The incoming or received waves will obviously be received with different intensities when coming from different directions.

They may arrive from such a direction that. .the'electromotive force induced in the wavereceiving aerial loops 1 and 2 is very feeble for one of the reversals. Under such conditions, the special transformer, equalizing the electromotive forces of the two reversals, will produce electromotive forces in its output that are feeble for both reversals. When the induced electromotive force in the aerial loops 1 and 2 is feeble for one of the reversals, therefore, detection is rendered very diflicult. The apparatus will then be so very insensitive that the indications will not be accurate. If the loop aerials are then turned through a suitable angle, say 45, the waves arriving along the least sensible directions will be received at a corresponding suitable angle, thus improving the operation of the vlevice. If the loops only were turned, it would be necessary to add or subtract the said angle to the angle read on the graduated scale. This may, however, be avoided by'turning the fixed winding of the trans-.

former through the same angle, for the movable winding will then occupy the same position relatively to the scale before and after the rotation. .The loops and the transformer may, therefore, be made adjustable though, as

winding of the transformer are maintained fixed during the signal-receiving operation. To effect this rotatable adjustment of the two planes of the loops and of the fixed part of the transformer 9, 10, 11, 12 through the desired angle, as an angle of 45, any.

desired mechanism may be'employed.

' It is preferred, however, to effect the rotatable adjustment of the loops and of the transformer winding electrically, rather than mechanically. To this end, the planes of eight individual loops (or equivalent windings) may preferably be symmetrically arranged around an axis 0, as shown in Fig. 5, where the loops are diagrammatically represented and numbered I to VIII, inclusive. Although the planes of the loops are shown as being in the plane of the figure, for clearness, it must be understood that they are supposed to be in vertical planes' and symmetrically disposed around the axis 0. The windings will be considered as in two groups, first, I, II, III and IV; and second, V, VI, VII and VIII. In the first group, the windings of the loops I, II, III and IV are connected in series, the senses of the windings of the first two loops being the same, but opposite to those of the other two. In the second group, the windings of the other four loops V, VI, VII, VIII are also connected in series, but all in the same direction. Each of these groups is electrically equivalent to a single phantom loop aerial with a defined plane and the planes of the two equivalent phantom loops thus formed are angularly disposed, i. e. perpendicular. Should these two groups be connected together in series, and in series also with the tuning condenser, while peri-y odically reversing the windings of one of the two groups, the assembly of these eight loops would alternately be equivalent to a fixedloop aerial and 'another' loop aerial perpendicular thereto. The operation otherwise is the same as already described.

Ifwe pass-to a second and similar arrangement of connections, in which each loop is replaced by the next following or the next preceding loop, the results will be the same as if all the loops had been mechanically turned through an angle of 45. All these loops, furthermore, will have remained symmetrically connected in the oscillating circuit formed by the loops and the v the axis 22 of these windings, and operable to cause the opening and closing of a series of contact members connected to the ends of the loop windings.

In the system of contact members illustrated in Figure 5, however, only a switching by hand is indicated in order to avoid confusion in the drawings. In this figure the switching is indicated as bein made by the set of blades M which may e thrown to the right or to the left to makethe two connections mentioned above.

For a normal operation, the set of blades relatively to the loops III and IV; and the ends of the resultant loop thus formed are connected to the brush 6 and to the amplifier in the same manner as loop 2, of Figure 1, is connected to the same brush and amplifier. It may also be seen that with the same switching, the loops V, VI, VII, VIII, are connected in series, all in the same direction, and the terminals of the resultant phantom loop thus formed are connected to thebrushes 4 and 5 in the same manner as the loop 1 is connected to the same brushes.

' When the set of blades M is thrown to the left, it may be seen by following the circuits, that, by this second switching, each group of loops, VIII, I, II, III, and IV, V,

VI, VII, are connected in series and the two resultant phantom loops thus formed 'are connected to the commutating ring 8 andto the amplifier in the same manner as loops 1 and 2 are connected, in Figs. 1 and 8, to the same commutating ring and amplifier.

If it is noticed that the loop VIII is now connected in a reversed direction" relatively to the'direction it had before, and also that the loop II had been reversed so as to have the same direction of winding as loopIII, it'is clear that by this second switching, the two systems of loops, I, II, III, IV, and V, VI, VII, VIII, of thefirst'switching have been replaced respectively by thetwo systems of loops VIII, I, II, III, and IV, V, VI, VII with the same relative directions of the loops. Therefore, by passing from the first switching to the second switching, an' operation, has been performed which is equivalent to a mechanical rotation of the ensemble of the lOopsthrough'anangle of 45. I So much for the adjustment of the loops.

nt of the'transformer, so as to produce e the windings 9 and 10 may each be divided into two equal parts 9a, 96, 10a, and 101;, as shown in Fig. 5 and Fig.- 6, where each effect a corresponding electrical adjust.

winding is diagrammatically represented.

For normal operation, the end 6 will be connected to the end 0 and the end f'to the end g; and the two" windings thus formed will be connected in series while periodically-re versing one or the other of them. .Whenentering zones of Weak sensibility, however,

the end 6 will be connected'to the end'g,

and the end f to the end (5; and the two 'windingsthus formed will be connected in series, whlle periodically reversing the sense of one of them. The effect of this change of electrical connections is the same as if the same effect as a 45 mechanical rotation,

windings had been mechanically turned through anangle of 45. This change of connections also may be effected in any well known way, as by cams and contact members, and at the same time as that .of the loop aerials.

In the switching of the transformer illustrated in Fig.)5, however, only a switching by hand is indicated in order to avoid confusion in the drawings. Asindicated in this figure, the switching is made'by the set of blades N which may be thrown to the right or the left to make the change of connections. v

For a normal operation the set of blades N is positioned onthe right. It may be readily seen that, with this first, switching, the primary coils of the transformer are connected to the commutating ring 32 and to the amplifier in the same manner as the connections of the transformer indicated in Figs. 1 and 8. I

'With the second switching (with the set of blades N to the left), it may beeasily.

seen, by following the circuits, that with the commutating ring-in the position indicated in Fig. 5, the coils 9a and 9b, of winding 9, are in series in the same direction, while the coils 10a and 10b, of winding 10, are connected in series in reversed directions; therefore, the resultant flux of the winding 10 is nil,and the resultant phantom coil for this commutation is constituted by the real winding 9. When the commutator 32 is turned through a right angle, relatively to what is shown in Fig. 5, C0llS 9a and 9b are connected in reverseddirections, and the coils 10a and 10?) are connected in the same direction; therefore, with this commutation, the resultant flux of the winding 9 is nil, and the resultant phantom'coil is constituted bythe real winding 10. Then, with the two alternate commutations, made by the rotation-of the commutator 32, the alternate resultant phantom coils are alternately coils equivalent to the windings 9 and 10. These phantom coilswith the switching just indicated (blades on tl1e left)' are at 45 relatively to the phantom coils. of the first switching (with set ofblades N to the right), since, as explained in relation to Figs. 1 and 8, the phantom coils in the latter case are at 45 relatively to the coils 9 and 10. Thus, by throwing the set of blades of switch N to the left, an operation equivalent to a mechanical rotation of the transformer; coils through 45 is accomplished. The switchin ofthe loops and of the transformer 'coi s must be performed simultaneously in order to turn the resultant loops and resultant transformer winding through 45? simultaneously. Thus, as explained before, the inaccuracies which may arise from weal-.- receptions "are avoided. j It is desirable, upon occasion, to compensate for deviations of aberrations .of the radio waves. These deviations may, or may not, be introduced by local causes. Among such are the deviations caused by the mass of the craft. These deviations are not constant, but vary with the angular position occupied by the movable transformer winding. The values of the errors caused by the deviations for various azimuths or angular positions of the movable transformer winding may be determined in advance, either experimentally, for each type of air plane, or by theoretical calculations. Such angle of correction may be allowed for, while still directing the craft with reference to the signal waves emitted from the sending station, merely by adjusting the position of the index or other indicator 3320f the instrument; normally, as by manipulating an indexcontrolling button or the like, or automatically as presently to be described. The index 332 will be under the control of the movable winding of the transformer, as previously described, except-that the index will thus be manually or automatically adjusted through the desired angle. The air plane will,therefore, make' 'the required, corrected angle, corresponding to the direction of the incoming waves.

According to the preferred embodiment of the invention that is herein illustrated and described, the necessary correction may be allowed for by adjustably mounting the index or other indicator 332 upon the axis 22 of the movable transformer winding, as illustrated in Fig. 7, from which the movable winding is omitted, for clearness. The indicator 332, shown as a needle, is here shown loosely-mounted on theaxis 22, instead of being fixed thereto, as described in connection with Figs. 4 and 8, and it bears, as by means of a spring 2,3,against acam 24. The shape of'the cam 24 has been previously determined, experimentally or theoretically, as before stated, so as automatically to correct for the necessary deviations, depending upon the'angular position occupied by the movable transformer winding. The cam 24 is fixed to a pinion 25 that is geared to a Iixed pinion 26 centered upon the movable winding axis 22. The axis of the pinion 25 turns with the axis 22 as a unit. When the axis .22 is turned, therefore, the cam 24 turns also: first, bodily about'the axis 22, moving the needle" with it, as before described, and without correction for errors; and, secondly, owing to the meshing engagement of the pinions 25 and 26, about the axis. of the pinion 25, giving thus a relative or correcting movementto the needle. The degree of this last-described movement of the needle is the required correction. Errors are thus automatically.compensated for by the cam 24, inaccordance with the angular position occupied by the movable transingsr V I A radiogoniometer having, 111 com- I former winding if, as before stated, the cam has previously been properly designed.

As before stated, of course,'the indicator needle 332 may be replaced by a movable graduated scale. It will also be understood that this correction may be made whether the apparatus is moved by the servo motor, or is under hand control.

The invention is not merely applicable to airplane and dirigible navigating, but it may be used anywhere, whether on land or at sea, and using any kind of craft, aerial, land or marine. 1

Other modifications, too, will occur to persons skilled in the art, and all such are considered to fall within the, spirit and scope of the present invention, as defined in the appended claims.

What is claimed is 1. A radiogoniometer comprising two -which the amplified currents are impressed,

said coupling means having a movable part for indicating directly the direction of the radio-wave source, a relay connected with said inductive coupling means so as to be operated thereby, a null-point indicator controlled'in accordance with the actuation of said relay, and means controlled by the relay for actuating the. movable part of the coupling means.

2. A radiogoniometrie device l1aving,i-n combination, a plurality of loops symmetr'ically disposed around an axis, means con necting the loops into circuit to provide a composite loop aerial pick-up arrangement equivalent to two resultant phantom loops having a constant angular disposition with respect to one another, means for relatively reversing the resultant phantom loops, and switchingmeans for rotating the resultant phantom loops through an angle correspond-ing to the angle between the symmetrically disposed loops.

, 3. In a radiogoniometer, an amplifier hav ing' an output circuit, a transformer connected in the output circuit and having plurality of parts, one of the parts comprising crossed windings and'the other part com-- prising one or more parallel windings, one of the parts being movable relatively to the other, and means for periodically reversing the connections of one of said crossed wind- 4. bination, an amplifier having an output cirwit, a transformer connected in said output circuit and having a primary winding and a secondary winding each having two parts,

its

Tan

a capacity in series with the primary winding, and impedance in Shunt to the primary winding, the parts of one of the windings being disposed at an angle to each other, and means for relatively reversing the con; nections ,of tl1e parts of one of the wind- 'ings.

5 In a rodiogoniometer, an amplifier having an output circuit, a transformer having two parts formingrespectively the primary and thesecondary, the primary being connected insaid output of the amplifier, one of the parts comprising crossed windings and the other part comprising one ormore parallel windings, one of .the parts being movable relatively to the other, means for periodically reversing the connections of one of said crossed windings, means for connectlng the secondary of the transformer in.

the input circuit ofan additional amplifier having an output circuit, a measuring instrumen't connected inqthe output circuit of the additional amplifier, and means f or pe= riodically reversing theconnections of saidmeasuring instrument in synchronism with said reversal of one of the crossed windings.

(5. In a; radiogoniometer, an amplifier having anoutput circuit, a transformer having two parts forming. respectively. the primary and the secbndary, the primary being con-f nected in said output circuit of the amplifier,

iii)

one of the parts comprising crossed windings and the other part comprising one or more parallel windin s, one of the parts being movable. relative y to the other, means for periodically reversing the connections of one of said crossed windings, means for connecting the secondary of the transformer in the input circuit of an additional amplifier having an output circuit, a measuring instrument,wmeans for periodically reversing the connections of said measuring .instrumentin synchronism with the reversal of one of the crossed windingsfland a Wheatstone bridge connected in the said output circuit of the additional amplifier the last tubeof said" additional amplifier being inserted in: one arm of the bridge, the plate of said tube being connected to one,.of the vertices and the cathode to the other vertex of said arm, the other arms of the bridge being constituted by resistances, the said instrument being connected tosaid one vertex and to the opposite vertex, and the plate current source being connected to the other two remaining opposite yertices.

1 73 A radiogoniometer having, in combination, two fixed crossed loops for receiving a signal from a station, means connecting the' T loops in series, means for relatively reversing the connections of the loops periodically, an inductive coupling means connected with the output of the loops andhaving .a movable part, and means controlled-by the electromot-ive forces in the inductivecoupling former connected with the output circuit having a primary windlng and a secondary.

winding each having two parts, a capacity in series with the primary winding, animpedance in shunt to the primary winding, the parts. of one of the windings being disposed at an angle to each other corresponding to the angle between the crossed loops, and. means for relatively reversing the connections of the parts of one of the windings in synchronisin with the relative reversal of the connections of the loops.-

9. A radiogoniometer having, in combination, two crossed loops for receiving a signal from a station andhaving an output circuit, means. for relatively reversing the connections of the loops, a-transformer having a primary winding and a secondary winding each having two parts, the parts of one of the windings being disposed at an angle to each other corresponding to the angle between the crossed loops, a motor and a circuit controlling the same, means connecting the primary winding in the output circuit, of the loops and the secondary in the circuit controlling the motor, respectively, means for relatively reversingthe connections of the parts of one of the windings synchronously with the relative, reversal of the loops, the loops and one of "the windings being fixed relativeto the other winding, the motor being mechanically connected to said other winding, and means controlled by the signal for actuating said motor to adjust said other winding in accordance with the location of the station. n

10. A radiogoniometer having, in combination, loops substantially symmetrically arranged around an axis, means connecting in series a group of the loops to form a resultant phantom loop, meansc'onnecting in series another group. of the loops to form anotherresultant phantom loop angularly winding anda, secondary winding, one of the windings being divided into a plurality of symmetrically disposed parts, means conmeeting the parts into two circuits, means connecting said two circults 1n series, means for periodically reversing the connection of one of said two circuits to provide two alternate angularly disposed resultant phantom coils, and switching, means for turning the resultant phantom coils through a predetermined angle. a

12.'In an apparatus having an inductive coupling means with a movable part adjusted to a osition corresponding to a desired, angullir relation of the craft relatively to the direction of a radio transmittin station, the method of indicating on a nu l-point indicator the deviation of the craft from said desired angular relation, comprising receiving two component parts of the radiant energy, alternately reversing one of the said component parts whereby two alternate resultant components are formed, resolving said two resultant components into two alternate electromotive forcesin the inductive coupling means, and utilizing the deviation from equality of saidelectromotive forces for actuating the' nullpoint indicator. 1

13. Apparatus of the character described having, in combination, a winding movable about an axis, an indicator controlled thereby, an error-correcting cam for controlling the indicator, the cam having a double movement of rotation about its own axis and the axis of the winding, and means controlled by the movement of'the winding for controllin the position of the cam.

' 14.. i radiogoniometer' which comprises two equivalent loops fixed with respect to each other, the loops being arranged in series relation and having an output circuit, the windings of said loops being electrically reversible with respect to each other, means for reversing the windings, means connected in'the' output circuit of the loops for amplifying the received signals, the amplifymg means having an output circuit, a transformer connected in the output circuit of the amplifying means and .upon which said amplified signals are impressed and having windings movable with respect to each other, a null-point instrument, connections for the instrument, meansfor moving said'transformer windings-relative to each other until they register equal current deviations on the instrument for each alternation of the current through loops, means for renersing for use on acraft .of the windings synchronously with the relative reversal of the loops, means connecting one of the windings with the loops, the loop and one of the windings being fixed relative to the other winding, 7

16. A radiogoniometer having, in combination, two crossed loops havingan output circuit, means for relatively reversing the connections of the loops periodically, a transformer having a primary winding and a secondary winding each having two parts, the parts of one of the windings being disposed at an angle to each other corresponding to the angle between the crossed loops,

means for relatively reversing the connectionsof the parts of one of the windings in synchronism with the relative reversal of the connections of the loops, means connecting the primary winding in the output circuit of the loops, the loops and one of the windings being fixed relativeto the other at an angle to each other corresponding to 1 the angle between the crossed loops, means for relatively reversing the connections of the parts of one of the windings in synchronism with the relative reversal of the connections of the loops, a relay, means connecting the primary winding in the output .cir- Y cuit of the loops and the secondary winding to' the relay, the loops and one of the windings being fixed relative to the other winding, and means controlled by the relay for relatively moving the said other winding in accordance with the location of the station.

18. A radiogom'ometer having, in combination, two crossed loops having an output circuit for receiving a signal from a station, means for relatively reversing the connections of the loops periodically, a transformer having a primary winding and a secondary winding each having two parts, the parts of one of the windings being disposed at an angle to each other corresponding to the angle between the crossed loops, means for relatively reversing the connections of the parts of one of the windings in synchro-' nism with the relative reversal'of the connections of the loops, a W'heatstone bridge, means connecting the primary winding in the output circuit of the loops and the secondary winding with two vertices of one arm of the Wheatstone bridge, the other means for relatively reversing the connec tions of the loops, a transformer having a primary winding and a secondary winding each having two parts, the parts of one of the windingsbemg disposed at an angle to each other corresponding to the angle between the crossed loops, means for rela- .tively reversing the connections of the parts of one of the windings, a relay, means connecting the primary "winding in the output circuit of the loops and the secondary winding with the relay. the loops and one of the windings being fixed relative to the other winding, and means controlled by the relay for relatively moving the said other winding in accordance with the location of the statio n, 'the transformer being calibrated to indicate the direction of the stazion when the relay is in its neutral posination, a'plurality of loops symmetrically arranged around an axis and having an output circuit, means connecting the loops as a composite loop aerial pickup arrangementequ valent to two resultant phantom loops having a constant angular disposition with respect to one another, a transformer having apr mary winding connected in the output clrcuit of the loops and a secondary winding, one of the windings being divided in a plurality of parts, means connecting the parts of the divided winding into a circuit equivalent to a resultant phantomcoil, and means for varying the connections of the loops and of the parts of the divided. winding of the transformer to efiect electrically a rotation of the resultant phantom loops and of the resultant phantom coils through the same angle.

21. A radiogoniometer having, in combination, loops substantially symmetrically arranged around an axis and having an output clrcuit, means connecting in series a group of loops to form a resultant phantom loop, means connecting in series another group of the loops in another resultantphantom 5C loop angularly disposed relatively to the first named phantom loop, means connecting the groups ;in series, means for relatively reversing periodically the connections of the groups, a transformer having a primary Winding and a secondary winding, the pri- 20. A radiogoniometer having, in combimary winding being connecteu in the output circuit of the loops, one of the windings be ing' divided into a plurality of symmetrically disposed parts, means connecting the parts into two circuits, means'connecting said two circuits in series,'means for periodically reversing the] connection of'one of said cir- V cuits in synchronism with the reversal of the connections of the loops to provide two alternate angularly disposed resultant phantoiu coils, and switching means for turning] reversal of the connections of the loops,

means connecting one of the windings with the loops, the loops and one of the windings being fixed relative to the other winding, means for relatively moving the saidother winding, the windings bei ng calibrated, an indicator movable synchronously with the said relative movementof the windings and cooperating with the calibrations of the calibrated transformer for indicating the location of the station, an error-correcting cam for correcting the indications of the indicator, and means controlled in accordance with the said relative movement of the saidother. winding for controlling the operation of the cam.

23. A radiogoniometer having, in-combination, two crossed loops for receiving a signal from a station and having an output circuit,.means for connecting the loops in series, means for relatively reversing alternately the connections of the loops, inductive coupling means connected with the output circuit of the loops-and having a mov! able part for indicatingthe direction of the station, and means for observing-the equal: ity of the electromotive forces induced in the said movable part during the two alternate relatively reversed connections of the loops.

24. A radiogoniometer having, in combination, two crossed loops for receiving a signal from a station, means for connecting the loops in series, means for relatively reversing alternately the connections of the loops, means for-equalizing the two alternate outputs of the loops comprising a transformer connected with the loops'and upon which the signals are impressed and having windings movable with respect to each other, and means for indicating the equality ofthe equalized outputs comprisinga null-point instrument, connections for the instrument, and means for moving said transformer windings relative to-each other until they' register equal current deviations on the instrument for each alternation of the current through said loops.

'a signal from a station, means connecting the loops in series, means for relatively re-.

versing the connections of the loops periodi- I cally, inductive coupling means having a movable part adjustable. to receive equal electromotive forces during the two reversed connections of the loops fora desired angular relation between an axis of the craft and y the direction of the station, and means controlled by the said movable part for indicating the deviations of the said axis of the craft from said angular relation.

27. The method of indicating the direction of a radio transmitting station by an inductive coupling means having a movable part, which comprises receiving two direc tional component parts of the radiant energy from said transmitting station, one of. ,said componentparts being alternately received in reversed directions whereby two alternate angularly disposed resultant components are received, resolving said two resultant components into two alternate electromotive forces in the inductive coupling means, and utilizing the deviation from equality of said two electromotive forces for actuatingsaid movable part of the inductive coupling means'to indicate the direction of the station.

28. The method of indicating the direction of a radio transmitting station by Y means of an inductive coupling means having primary and secondary windings one of the windings being movable, which comprises receiving two directional component .parts of the radiant energy from said transmitting station one of said component parts being alternatelyreceived in reversed direction whereby two alternate angularly disposed resultant components are received, resolving each of said resultant components into two subsequent directional components in the primary of the inductive coupling means; reversing one of said subsequent di: rectional components synchronously with said reversed receptions of one of the component parts of the radiant energy whereby two subsequent alternate resultant components are formed in the inductive coupling means, resolving said two subsequent resultant components into two alternate electromotive forces in the 'secondary of the deviation from equality of said two elec-- tromotive forces for actuating the direction indicating means.

HAIG ANTRAm I'AN,

inductive coupling means, and utilizing the 

